Netctl is a CLI-based tool used to configure and manage network connections via profiles. It is a native Arch Linux project that replaces the old ''netcfg'' utility.

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''netctl'' is a CLI-based tool used to configure and manage network connections via profiles. It is a native Arch Linux project that replaces the old ''netcfg'' utility.

== Installation ==

== Installation ==

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{{Expansion|Optional dependencies should be mentioned.}}

The {{Pkg|netctl}} package is available in the [[official repositories]]. Installing netctl will replace {{AUR|netcfg}}.

The {{Pkg|netctl}} package is available in the [[official repositories]]. Installing netctl will replace {{AUR|netcfg}}.

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{{Pkg|netctl}} and {{AUR|netcfg}} are conflicting packages. You will be potentially connectionless after installing '''netctl''' if your profiles are misconfigured.

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{{Pkg|netctl}} and {{AUR|netcfg}} are conflicting packages. You will be potentially connectionless after installing ''netctl'' if your profiles are misconfigured.

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{{Note|It may be a good idea to use {{ic|1=systemctl --type=service}} to ensure that no other service is running that may want to configure the network. Multiple networking services will conflict.}}

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{{Note|It may be a good idea to use {{ic|1=systemctl --type=service}} to ensure that no other service is running that may want to configure the network. Multiple networking services will conflict.}}

== Required reading ==

== Required reading ==

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== Configuration ==

== Configuration ==

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{{ic|netctl}} may be used to introspect and control the state of the systemd services for the network profile manager. Example configuration files are provided for the user to assist them in configuring their network connection. These example profiles are located in {{ic|/etc/netctl/examples/}}. The common configurations include:

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''netctl'' uses profiles to manage network connections, profile files are stored in {{ic|/etc/netctl/}}. Example configuration files are provided for the user to assist them in configuring their network connection. These example profiles are located in {{ic|/etc/netctl/examples/}}. The common configurations include:

* ethernet-dhcp

* ethernet-dhcp

* ethernet-static

* ethernet-static

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* wireless-wpa-static

* wireless-wpa-static

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For wireless settings, use '''wifi-menu -o''' will generate the config file in /etc/netctl.

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To use an example profile, simply copy one of them from {{ic|/etc/netctl/examples/}} to {{ic|/etc/netctl/}} and configure it to your needs:

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To use an example profile, simply copy one of them from {{ic|/etc/netctl/examples/}} to {{ic|/etc/netctl/}} and configure it to your needs:

# cp /etc/netctl/examples/wireless-wpa /etc/netctl/''profile''

# cp /etc/netctl/examples/wireless-wpa /etc/netctl/''profile''

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{{Tip|For wireless settings, you can use {{ic|wifi-menu -o}} to generate the profile file in {{ic|/etc/netctl/}}.}}

Once you have created your profile, make an attempt to establish a connection using the newly created profile by running:

Once you have created your profile, make an attempt to establish a connection using the newly created profile by running:

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# netctl start ''profile''

# netctl start ''profile''

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{{Note|'profile' is the file name, not including the full path. Providing the full path will make netctl return with an error code.}}

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{{Note|''profile'' is the file name, not including the full path. Providing the full path will make ''netctl'' exit with an error code.}}

If issuing the above command results in a failure, then use {{ic|journalctl -xn}} and {{ic|netctl status ''profile''}} in order to obtain a more in depth explanation of the failure. Make the needed corrections to the failed configuration and retest.

If issuing the above command results in a failure, then use {{ic|journalctl -xn}} and {{ic|netctl status ''profile''}} in order to obtain a more in depth explanation of the failure. Make the needed corrections to the failed configuration and retest.

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=== Automatic operation ===

=== Automatic operation ===

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If you use only one profile (per interface) or want to switch profiles manually, the [[#Basic method|basic method]] will do. Most common examples are servers, workstations, routers etc.

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If you use only one profile (per interface) or want to switch profiles manually, the [[#Basic method|Basic method]] will do. Most common examples are servers, workstations, routers etc.

If you need to switch multiple profiles frequently, use [[#Automatic switching of profiles|Automatic switching of profiles]]. Most common examples are laptops.

If you need to switch multiple profiles frequently, use [[#Automatic switching of profiles|Automatic switching of profiles]]. Most common examples are laptops.

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==== Basic method ====

==== Basic method ====

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With this method, you can statically start only one profile per interface. First manually check that the profile can be started successfully, then it can be {{ic|enabled}} using

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With this method, you can statically start only one profile per interface. First manually check that the profile can be started successfully, then it can be enabled using

# netctl enable ''profile''

# netctl enable ''profile''

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==== Automatic switching of profiles ====

==== Automatic switching of profiles ====

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{{ic|netctl}} provides two special '''systemd''' services for automatic switching of profiles: {{ic|netctl-auto@''interface''.service}} for wireless interfaces, and {{ic|netctl-ifplugd@''interface''.service}} for wired interfaces. Using {{ic|netctl-auto@''interface''.service}}, netctl profiles change as you move from range of one network into range of other network. Using {{ic|netctl-ifplugd@''interface''.service}}, netctl profiles change as you plug the cable in and out.

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''netctl'' provides two special [[systemd]] services for automatic switching of profiles:

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{{Note|{{ic|netcfg}} used {{ic|net-auto-wireless.service}} and {{ic|net-auto-wired.service}} for this purpose.}}

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* For wired interfaces: {{ic|netctl-ifplugd@''interface''.service}}. Using this netctl profiles change as you plug the cable in and out.

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* For wireless interfaces: {{ic|netctl-auto@''interface''.service}}. Using this netctl profiles change as you move from range of one network into range of other network.

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{{Note|''netcfg'' used {{ic|net-auto-wireless.service}} and {{ic|net-auto-wired.service}} for this purpose.}}

First [[pacman|install]] required packages:

First [[pacman|install]] required packages:

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* Package {{Pkg|ifplugd}} is required to use {{ic|netctl-ifplugd@''interface''.service}}.

* Package {{Pkg|ifplugd}} is required to use {{ic|netctl-ifplugd@''interface''.service}}.

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Now configure all profiles that {{ic|netctl-auto@''interface''.service}} or {{ic|netctl-ifplugd@''interface''.service}} can start. If you want some profile '''not''' to be started automatically by these services, you have to explicitly add {{ic|1=ExcludeAuto=yes}} to that profile. You can use {{ic|1=Priority=}} to set priority of some profile when multiple profiles are available. See {{ic|netctl.profile(5)}} for details.

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Now configure all profiles that {{ic|netctl-auto@''interface''.service}} or {{ic|netctl-ifplugd@''interface''.service}} can start.

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If you want some wireless profile '''not''' to be started automatically by {{ic|netctl-auto@''interface''.service}}, you have to explicitly add {{ic|1=ExcludeAuto=yes}} to that profile. You can use {{ic|1=Priority=}} to set priority of some profile when multiple profiles are available. {{ic|netctl-ifplugd@''interface''.service}} will prefer profiles, which use [[Wikipedia:DHCP|DHCP]]. To prefer a profile with a static IP, you can use {{ic|1=AutoWired=yes}}. See {{ic|netctl.profile(5)}} for details.

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{{Warning|Automatic selection of a WPA-enabled profile by ''netctl-auto'' is not possible with option {{ic|1=Security=wpa-config}}, please use {{ic|1=Security=wpa-configsection}} instead.}}

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{{Warning|Automatic selection of a WPA-enabled profile by netctl-auto is not possible with option {{ic|1=Security=wpa-config}}, please use {{ic|1=Security=wpa-configsection}} instead.}}

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Once your profiles are set and verified to be working, simply enable these services using ''systemctl'':

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Once your profiles are set and verified to be working, simply enable these services through systemd with

# systemctl enable netctl-auto@''interface''.service

# systemctl enable netctl-auto@''interface''.service

# systemctl enable netctl-ifplugd@''interface''.service

# systemctl enable netctl-ifplugd@''interface''.service

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{{Warning|If any of the profiles contain errors, such as an empty {{ic|1=Key=}} variable, the unit will fail to load at boot.}}

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{{Warning|

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* If any of the profiles contain errors, such as an empty {{ic|1=Key=}} variable, the unit will fail to load at boot.

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{{Warning|Ensure you include the ''interface'' name when enabling the systemd service. Failure to do so will result in a unit named "netctl-auto@multi-user.service", which will need to be disabled.}}

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* This method conflicts with the [[#Basic method|Basic method]]. If you have previously enabled a profile through ''netctl'', run {{ic|netctl disable ''profile''}} to prevent the profile from starting twice at boot.}}

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{{Warning|This method conflicts with the [[#Basic method|basic method]]. If you have previously enabled a profile through {{ic|netctl}}, run {{bc|# netctl disable ''profile''}} to prevent the profile from starting twice at boot.}}

* Unlike {{ic|netcfg}}, by default {{ic|netctl}} fails to bring up a [[wikipedia:Network interface controller|NIC]] when it is not connected to another powered up NIC. To solve this problem, add {{ic|1=SkipNoCarrier=yes}} at the end of your {{ic|/etc/netctl/''profile''}}.

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* Unlike ''netcfg'', by default ''netctl'' fails to bring up a [[wikipedia:Network interface controller|NIC]] when it is not connected to another powered up NIC. To solve this problem, add {{ic|1=SkipNoCarrier=yes}} at the end of your {{ic|/etc/netctl/''profile''}}.

=== Passphrase obfuscation (256-bit PSK) ===

=== Passphrase obfuscation (256-bit PSK) ===

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{{Note|

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* Although "encrypted", the key that you put in the profile configuration is enough to connect to a WPA-PSK network. Therefore this process is only useful for hiding the human-readable version of the passphrase. This will not prevent anyone with read access to this file from connecting to the network. You should ask yourself if there is any use in this at all, since using the same passphrase for anything else is a very poor security measure.

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Users ''not'' wishing to have the passphrase to their wireless network stored in ''plain text'' have the option of storing the corresponding 256-bit pre-shared key (PSK) instead, which is calculated from the passphrase and the SSID using standard algorithms.

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* Method 1: Use {{ic|wifi-menu -o}} to generate a config file in {{ic|/etc/netctl}}

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{{Note|Although "encrypted", the key that you put in the profile configuration is enough to connect to a WPA-PSK network. Therefore this process is only useful for hiding the human-readable version of the passphrase. This will not prevent anyone with read access to this file from connecting to the network. You should ask yourself if there is any use in this at all, since using the same passphrase for anything else is a very poor security measure.}}

Users '''not''' wishing to have the passphrase to their wireless network stored in ''plain text'' have the option of storing the corresponding 256-bit pre-shared key (PSK) instead, which is calculated from the passphrase and the SSID using standard algorithms.

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* Method 1: Use {{ic|wifi-menu -o}} to generate a config file in {{ic|/etc/netctl/}}

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* Method 2: Manual settings as follows.

For both methods it is suggested to {{ic|chmod 600 /etc/netctl/<config_file>}} to prevent user access to the password.

For both methods it is suggested to {{ic|chmod 600 /etc/netctl/<config_file>}} to prevent user access to the password.

{{Note|This information will be used in your profile, so do not close the terminal.}}

{{Note|This information will be used in your profile, so do not close the terminal.}}

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}}

In a second terminal window, copy the example file {{ic|wireless-wpa}} from {{ic|/etc/netctl/examples}} to {{ic|/etc/netctl}}:

In a second terminal window, copy the example file {{ic|wireless-wpa}} from {{ic|/etc/netctl/examples}} to {{ic|/etc/netctl}}:

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# cp /etc/netctl/examples/wireless-wpa /etc/netctl/wireless-wpa

# cp /etc/netctl/examples/wireless-wpa /etc/netctl/wireless-wpa

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You will then need to edit {{ic|/etc/netctl/wireless-wpa}} using your favorite text editor and add the ''pre-shared key'', that was generated earlier using wpa_passphrase, to the {{ic|'''Key'''}} variable of this profile.

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You will then need to edit {{ic|/etc/netctl/wireless-wpa}} using your favorite text editor and add the ''pre-shared key'', that was generated earlier using wpa_passphrase, to the {{ic|Key}} variable of this profile.

* Make sure to use the '''special non-quoted rules''' for {{ic|1=Key=}} that are explained at the end of [https://github.com/joukewitteveen/netctl/blob/master/docs/netctl.profile.5.txt netctl.profile(5)].

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* Make sure to use the '''special quoting rules''' for the {{ic|Key}} variable as explained at the end of [https://github.com/joukewitteveen/netctl/blob/master/docs/netctl.profile.5.txt netctl.profile(5)].

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}}

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* If the passphrase fails, try removing the {{ic|\"}} in the {{ic|Key}} variable.}}

This example describes how to use ''bonding'' to fallback to wireless when the wired ethernet goes down. The presence of network connection on each interface is detected and ''dhcpcd'' is started when connection on either or both interfaces is established.

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You'll need additional packages from the official repositories: {{Pkg|ifplugd}}, {{Pkg|ifenslave}} and {{Pkg|wpa_supplicant}}.

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First configure the {{ic|bonding}} driver to use {{ic|active-backup}}:

Next, configure a netctl profile to enslave the two hardware interfaces:

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{{hc|/etc/netctl/failover|2=

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Description='A wired connection with failover to wireless'

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Interface='bond0'

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Connection=bond

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BindsToInterfaces=('eth0' 'wlan0')

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IP='no'

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SkipNoCarrier='no'

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}}

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Enable the profile on startup.

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# netctl enable failover

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Configure ''wpa_supplicant'' to associate with known networks. This can be done with a netctl profile (remember to use {{ic|1=IP='no'}}) and a ''wpa_supplicant'' service running constantly, or on-demand with ''wpa_cli''. Ways to do this are covered on the [[wpa_supplicant]] page.

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Create an ''ifplugd'' action for automatic DHCP assignment on the bonded interface:

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{{hc|/etc/ifplugd/bond_dhcp.action|2=

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#!/bin/sh

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case "$2" in

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up)

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systemctl start "dhcpcd@$1.service" && exit 0

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;;

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down)

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systemctl stop "dhcpcd@$1.service" && exit 0

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;;

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*)

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echo "Wrong arguments" > /dev/stderr

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;;

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esac

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exit 1

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}}

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and make it executable

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# chmod +x /etc/ifplugd/bond_dhcp.action

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Then create the [[systemd]] service which starts ''ifplugd'' for {{ic|bond0}}:

If you have a wired and wireless connection to the same network, you can probably now disconnect and reconnect the wired connection without losing connectivity. In most cases, even streaming music won't skip!

Required reading

Configuration

netctl uses profiles to manage network connections, profile files are stored in /etc/netctl/. Example configuration files are provided for the user to assist them in configuring their network connection. These example profiles are located in /etc/netctl/examples/. The common configurations include:

ethernet-dhcp

ethernet-static

wireless-wpa

wireless-wpa-static

To use an example profile, simply copy one of them from /etc/netctl/examples/ to /etc/netctl/ and configure it to your needs:

# cp /etc/netctl/examples/wireless-wpa /etc/netctl/profile

Tip: For wireless settings, you can use wifi-menu -o to generate the profile file in /etc/netctl/.

Once you have created your profile, make an attempt to establish a connection using the newly created profile by running:

# netctl start profile

Note:profile is the file name, not including the full path. Providing the full path will make netctl exit with an error code.

If issuing the above command results in a failure, then use journalctl -xn and netctl status profile in order to obtain a more in depth explanation of the failure. Make the needed corrections to the failed configuration and retest.

Automatic operation

If you use only one profile (per interface) or want to switch profiles manually, the Basic method will do. Most common examples are servers, workstations, routers etc.

Basic method

With this method, you can statically start only one profile per interface. First manually check that the profile can be started successfully, then it can be enabled using

# netctl enable profile

This will create and enable a systemd service that will start when the computer boots.

Note: The connection is only established if the profile can be started succesfully at boot time (or when the service starts). That specifically means, in case of wired connection the cable must be plugged-in, in case of wireless connection the network must be in range.

Tip: To enable static IP profile on wired interface no matter if the cable is connected or not, use SkipNoCarrier=yes in your profile.

Automatic switching of profiles

netctl provides two special systemd services for automatic switching of profiles:

For wired interfaces: netctl-ifplugd@interface.service. Using this netctl profiles change as you plug the cable in and out.

For wireless interfaces: netctl-auto@interface.service. Using this netctl profiles change as you move from range of one network into range of other network.

Note:netcfg used net-auto-wireless.service and net-auto-wired.service for this purpose.

Now configure all profiles that netctl-auto@interface.service or netctl-ifplugd@interface.service can start.

If you want some wireless profile not to be started automatically by netctl-auto@interface.service, you have to explicitly add ExcludeAuto=yes to that profile. You can use Priority= to set priority of some profile when multiple profiles are available. netctl-ifplugd@interface.service will prefer profiles, which use DHCP. To prefer a profile with a static IP, you can use AutoWired=yes. See netctl.profile(5) for details.

Warning: Automatic selection of a WPA-enabled profile by netctl-auto is not possible with option Security=wpa-config, please use Security=wpa-configsection instead.

Once your profiles are set and verified to be working, simply enable these services using systemctl:

For static IP configuration make sure the Address variables have a netmask after the IP (e.g. Address=('192.168.1.23/24' '192.168.1.87/24') in the example profile).

If you setup a wireless profile according in the wireless-wpa-configsection example, note that this overrides wpa_supplicant options defined above the brackets. For a connection to a hidden wireless network, add scan_ssid=1 to the options in the wireless-wpa-configsection; Hidden=yes does not work there.

Unlike netcfg, by default netctl fails to bring up a NIC when it is not connected to another powered up NIC. To solve this problem, add SkipNoCarrier=yes at the end of your /etc/netctl/profile.

Passphrase obfuscation (256-bit PSK)

Note: Although "encrypted", the key that you put in the profile configuration is enough to connect to a WPA-PSK network. Therefore this process is only useful for hiding the human-readable version of the passphrase. This will not prevent anyone with read access to this file from connecting to the network. You should ask yourself if there is any use in this at all, since using the same passphrase for anything else is a very poor security measure.

Users not wishing to have the passphrase to their wireless network stored in plain text have the option of storing the corresponding 256-bit pre-shared key (PSK) instead, which is calculated from the passphrase and the SSID using standard algorithms.

Method 1: Use wifi-menu -o to generate a config file in /etc/netctl/

Method 2: Manual settings as follows.

For both methods it is suggested to chmod 600 /etc/netctl/<config_file> to prevent user access to the password.

Bonding

The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical "bonded" interface. The behavior of the bonded interfaces depends on the mode. Generally speaking, modes provide either hot standby or load balancing services. Additionally, link integrity monitoring may be performed.

Load balancing

To use bonding with netctl, additional package from official repositories is required: ifenslave.

Copy /etc/netctl/examples/bonding to /etc/netctl/bonding and edit it, for example:

Now you can disable your old configuration and set bonding to be started automatically. Switch to the new profile, for example:

# netctl switch-to bonding

Note: This uses the round-robin policy, which is the default for the bonding driver. See official documentation for details.

Tip: To check the status and bonding mode:

$ cat /proc/net/bonding/bond0

Wired to wireless failover

This example describes how to use bonding to fallback to wireless when the wired ethernet goes down. The presence of network connection on each interface is detected and dhcpcd is started when connection on either or both interfaces is established.

Configure wpa_supplicant to associate with known networks. This can be done with a netctl profile (remember to use IP='no') and a wpa_supplicant service running constantly, or on-demand with wpa_cli. Ways to do this are covered on the wpa_supplicant page.

Create an ifplugd action for automatic DHCP assignment on the bonded interface:

If you have a wired and wireless connection to the same network, you can probably now disconnect and reconnect the wired connection without losing connectivity. In most cases, even streaming music won't skip!